In the Rule entitled “Stats and Equipment”, change the text

There exist Armors, which are a type of item. An Armor has an integer amount of AC, which cannot be negative. If an @ carries an Armor, they may be wearing it.

to

There exist Armors, which are a type of item. An Armor has an integer amount of AC, which cannot be negative. An Armor is one of 7 Armor Types: Helm, Cloak, Body Armor, Shirt, Shield, Gloves, and Boots. If an @ carries an Armor, they may be wearing it.

In the Rule entitled “Wielding, Wearing, and Enchantment”, change the text

An @ may only wear one armor at a time.
The weapon an @ is currently wielding, and the armor they are currently wearing, are each tracked in GNDT columns, which both default to “None”.

to

An @ may only wear one armor of each Armor Type at a time.
The weapon an @ is currently wielding, and all the the armor they are currently wearing, are each tracked in GNDT columns, which both default to “None”.

In the Rule entitled “Combat”, change the text

The RNG shall role XDICEY in the GNDT where X is the Monster’s Dice and Y is the Monster’s Sides, subtract from that the AC of any armor the @ is wearing and, if the result is a positive number, decrease the @‘s HP by the result.

to

The RNG shall role XDICEY in the GNDT where X is the Monster’s Dice and Y is the Monster’s Sides, subtract from that the AC of all armor the @ is wearing and, if the result is a positive number, decrease the @‘s HP by the result.

In the Rule entitled “Armor List”, change the text

The items listed in this table are armors, with Base AC as specified.

to

The items listed in this table are armors, with Base AC and Armor Type as specified.

Add a “Armor Type” column to the list in that rule.  Give Ring Mail and Leather Armor an Armor Type of “Body Armor”, Robe and Cloak of Magic Resistance an Armor Type of “Cloak”, Small Shield an Armor Type of “Shield”, and Hawaiian Shirt an Armor Type of “Shirt”.